Giant NLO response and deep ultraviolet transparency of dual (alkali/alkaline earth) metals doped C₆O₆Li₆ electrides

The designing of new materials having outstanding nonlinear optical (NLO) response is much needed for use in latest optics. Herein, the geometric, electronic and NLO properties of alkali and alkaline earth metals doped C₆O₆Li₆ (alk-C₆O₆Li₆-alkearth, alkearth = Ca, Mg, Be and alk = K, Na, Li) electrides is studied via quantum chemical approach. The interaction energies (E_int) are examined to illustrate their thermodynamic stability. The strong interaction energy of -39.99 kcal mol^-1 is observed for Ca–C₆O₆Li₆–Li electride in comparison to others. Frontier molecular orbitals (FMOs) energy gap of considered complexes is changed due to the electronic density shifting between metals and C₆O₆Li₆ surface, which notifies the semi conducting properties of these electrides. The FMOs isodensities and natural bond orbital (NBO) charge analysis are performed to justify charge transfer between dopants and complexant. UV–Visible study also confirmed the application of these electrides as deep ultra-violet laser devices. NLO response is studied through calculation of first hyperpolarizability (β_o). The highest β_o value of 1.68 × 10⁵ au is calculated for Mg–C₆O₆Li₆–K electride. NLO response is further rationalized by three- and two-level models approach.